I got an order from Tindie last night. I had issues with my DIY stepper based rotary encoder so when I saw TYMKRS “Turn Me v1” kit I had no hesitation parting with $10. It seemed to only come with Arduino sample code so I wrote my own code. My code is written in assembly for the PIC because that’s my preferred microcontroller and I’m not much of a C programmer. I happened to get another pair of Jayson Tautic’s 20 Pin Development Boards. Check out his Tindie store.. he has a bunch of interesting things. If I still lived in the midwest I’d pick up that lightning detector. (Jayson, if you ever read this your fan’s request more awesomness)
These wasn’t a ton of sample code online … some 16F88 code I didn’t care for… 16F84 code that was wretched… and some interrupt driven code I wasn’t feeling either so I wrote my own polling code from scratch. It’s commented enough to get what I was doing. The schematic should be fairly obvious, not counting the LED resistors I used a pull down resistor on the switch built into the encoder.
To my knowledge, while writing the code, I had my very first stack overflow bug!
The important stuff:
;******************************************************************************* ; Rotary Encoder Test, 2 bit * ; http://www.iradan.com ; ; RA0: OUT TEST LED ; RA1: IN ENC_B INPUT, NOTE: DISCONNECT OR INSURE LOW WHEN PROGRAMMING ; RA2: IN ENC_A INPUT ; RB5: OUT SWITCH STATUS LED ; RB7: IN SWITCH INPUT ; RC<0:7> OUT ENCODER "COUNT" ; ; VERSION 0.1 INITIAL CODE ; ;******************************************************************************* errorlevel -230, -302, -303, -313 LIST R=DEC #include "p16f1509.inc" __CONFIG _CONFIG1, _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _CLKOUTEN_OFF __CONFIG _CONFIG2, _LVP_OFF & _STVREN_ON UDATA_SHR COUNT RES .1 ENC_LAST RES .1 ENC_CURRENT RES .1 #DEFINE ENCA PORTA,1 #DEFINE ENCB PORTA,2 #DEFINE ENC_SA ENC_LAST,0 #DEFINE ENC_SB ENC_LAST,1 #DEFINE ENCA_NOW ENC_CURRENT,0 #DEFINE ENCB_NOW ENC_CURRENT,1 ;******************************************************************************* ; Reset Vector ;******************************************************************************* RES_VECT CODE 0x0000 ; processor reset vector GOTO START ; go to beginning of program ;******************************************************************************* ; MAIN PROGRAM ;******************************************************************************* MAIN_PROG CODE ; let linker place main program START CALL INIT BANKSEL PORTA BSF PORTA,0 ;THIS WAS FOR TESTING. GOTO LOOP INIT CLRF COUNT BANKSEL PORTC CLRF PORTC BANKSEL LATC ;Data Latch CLRF LATC ; BANKSEL ANSELC ; CLRF ANSELC ;Digital IO BANKSEL TRISC ; MOVLW B'00000000' ;RC<0:7> OUT MOVWF TRISC BANKSEL PORTA ; CLRF PORTA ;Init PORTA BANKSEL LATA ;Data Latch CLRF LATA ; BANKSEL ANSELA ; CLRF ANSELA ;digital I/O BANKSEL TRISA ; MOVLW B'00111110' ;Set RA<0,6:7>out RA<1:5> in MOVWF TRISA ; BANKSEL TRISB MOVLW B'11011111' ;RB<5> OUT, RB<0:4>,<6:7> IN MOVWF TRISB CLRF PORTB BANKSEL OSCCON ;SET OSCILLATOR SPEED MOVLW 0x78 ;01111000 / 16MHz MOVWF OSCCON CLRF ENC_CURRENT ;HOUSE KEEPING CLRF ENC_LAST RETURN LED BANKSEL PORTB ;THIS TURNS ON SWITCH STATUS LED BSF PORTB,5 RETURN INCR INCF COUNT,f ; GOTO RESUME RETURN DECR DECF COUNT,f ; GOTO RESUME RETURN DETERMINE_DIRA BTFSC ENCB_NOW ;OKAY WHICH WAY DID IT TURN? CALL INCR ;INCREMENT BTFSS ENCB_NOW CALL DECR ;DECREMENT RETURN TESTLASTA BTFSS ENC_SA ;SO ENCA WAS HIGH, WAS IT LAST TIME? CALL DETERMINE_DIRA ;YEP.. NOP ;GUESS NOT, RETURNING RETURN TEST_ENC ;I'M ONLY TESTING FOR A HIGH ON ENC A. BTFSC ENCA_NOW ;THAT MEANS EVERY OTHER TICK ON THE ENCODER CALL TESTLASTA ;DOES NOTHING RETURN LOOP NOP BANKSEL PORTB BCF PORTB,5 ;TURN OFF SWITCH STATUS LED BANKSEL PORTA BTFSC PORTA,5 ;TEST IF SWITCH IS PUSHED CALL LED ;BRANCH IF ON, SKIP IF NOT NOP BCF ENCA_NOW ;CLEAR CONTENTS OF ENCODER "NOW BITS" BCF ENCB_NOW BANKSEL PORTA BTFSC ENCA BSF ENCA_NOW ;ENC_A INPUT IS HIGH NOP BTFSC ENCB BSF ENCB_NOW ;ENC_V INPUT IS HIGH CALL TEST_ENC ;TEST ENC_A BANKSEL PORTC ;DUMP ENCODER COUNT ONTO PORTC MOVFW COUNT MOVWF PORTC BCF ENC_SA ;SAVE STATUS OF ENCODER A & B INPUTS BTFSC ENCA_NOW BSF ENC_SA BCF ENC_SB BTFSC ENCB_NOW BSF ENC_SB BANKSEL PORTA ;USED FOR TESTING BCF PORTA,0 GOTO LOOP ;LOOP FOREVER END
